Many monitoring systems have been designed for observing and controlling a specific condition within an area or compartment and creating an alarm signal when there is a malfunction within the system. For example, many systems have been designed to monitor and control the temperature of a refrigerated area or compartment, such as a refrigerated room within a supermarket, or a refrigerated trailer as it is being towed by a truck. Such systems are necessary to protect a high investment in food products, or manufacturing processes, or even animals. Specifically, a refrigerated trailer might be transporting food products at temperatures below freezing. A trailer might be transporting chemicals at extremely low temperatures. A chemical process plant be refrigerating, or heating, a chemical process within certain controllable limits. Or, a trailer might be transporting live animals under temperature conditions which need to be comfortable and healthful.
Some of the typical monitoring systems found in the prior art are described in the following U.S. Pat. Nos. :
2,753,692, Dickieson, Jr., July 10, 1956
2,994,858, Coffer, Aug. 1, 1961
3,100,383, Foster et al, Aug. 13, 1963
3,441,929, Coffer et al, April 29, 1969
3,954,752, Atton, July 20, 1971
4,024,495, O'Brien, May 17, 1977
4,146,085, Wills, Mar. 27, 1979
4,187,093, Boratgis et al, Feb. 5, 1980
4,283,921, Prosky, Aug. 18, 1981
4,307,775, Saunders et al, Dec. 29, 1981
4,313,308, Boratgis et al, Feb. 2, 1982
4,325,223, Cantley, Apr. 20, 1982
Therefore, the primary object of my invention is to provide a monitoring system for a unit which is efficient, easy to operate, and inexpensive.
Another object of my invention is to provide a monitoring system for a unit or area which is adaptable to observe a condition of that unit or area and respond to control means for that condition.
Still another object of my invention is to provide a monitoring system for a unit or area which is adaptable to observe a condition of that unit or area and provide a malfunction signal if that condition reaches an undesirable status.
Still another object of my invention is to provide a monitoring system for a unit or area which system is adaptable to observe a condition of that unit or area and transpond a signal to a remote receiver.
A still further object of my invention is to provide a monitoring system which will respond to a physical state of a compartment and provide an alarm signal if the physical state should be undesirable.